Problem: There are 4 representatives from each of 4 companies at a convention. At the start of the convention, every person shakes hands once with every person except the other representatives from their company. How many handshakes are there?
All 16 people shake hands with 12 other people (everyone except themselves and the other representatives from their company).  In multiplying $16 \times 12$, each handshake is counted twice, so we divide by two to get the answer of $\dfrac{16 \times 12}{2} = \boxed{96}$ handshakes.